CH. 20 COMPREHENSIVE exzam pt 2

The "lubb" sound (first heart sound) of the heart is caused by the

closing of the AV valves.

Increased parasympathetic stimulation of the heart

decreases the heart rate.

While the semilunar valves are open during a normal cardiac cycle, the pressure in the left ventricle is

greater than the pressure in the aorta.

Cardiac output is defined as

heart rate times stroke volume.

A decrease in blood pH and an increase in blood carbon dioxide levels result in

increased heart rate. increased stroke volume. increased sympathetic stimulation of the heart. AND increased cardiac output.

Increased venous return results in

increased stroke volume. AND increased cardiac output.

Pressure in the aorta is at its lowest

just before the semilunar valves open.

Parasympathetic nerve fibers are found in the _____________ nerves and release _____________ at the heart.

vagus, acetylcholine

The pressure within the left ventricle fluctuates between

120 and 0 mm Hg.

An increase in extracellular potassium levels could cause

a decrease in heart rate.

Stroke volume is the

difference between end-diastolic and end-systolic volume.

The greatest amount of ventricular filling occurs during

the first one-third of diastole.

Because of the baroreceptor reflex, when normal arterial blood pressure decreases

the frequency of afferent action potentials from baroreceptors decreases.

Blood flows neither into nor out of the ventricles during

the period of isovolumic contraction. AND the period of isovolumic relaxation.

Just after the dicrotic notch on the aortic pressure curve,

the pressure in the aorta is greater than the pressure in the left ventricle.